A common design for crankshaft dampers comprises a metal hub, a metal pulley (inertia ring), and an elastomer sandwiched between the two metal parts. Generally, both metal parts are made from castings. However, some designs have a cast hub and a sheet metal formed pulley or vice versa. Dampers may also be made with formed sheet metal for both the hub and pulley.
The elastomer is usually retained between the metal parts by compression after being forced into the annular space between the two metal parts, with or without chemical bonding. In the case of chemical bonding, the most common agents are adhesives, for example, wet, dry, heat cure, chemical cure and so on. Chemical bonding agents are strong, but can be costly. Chemical bonding agents can also be environmentally unfriendly since many technically acceptable chemical adhesives are solvent based. They can also be very sensitive to process variables. Chemical bonding agents can fail by excessive heat, for example, in a paint oven or adhesive cure oven, by lack of proper cleaning of the components, by exposure to ambient conditions over time, and so on. Therefore, there is a need for a simpler, and more robust process of locking the elastomer between the two metal parts.
Representative of the art is U.S. Pat. No. 5,540,626 (1996) to Asai et al. which discloses a central portion, a belt retaining portion made of metal plate, and a ring-shaped rubber or elastic member placed therebetween. The central portion includes a flange. The flange and the belt retaining portion can have projections which compress the rubber or elastic member to hold it securely in place.
The prior art projections are not cooperatively arranged and only rely upon a compression of the elastic member by pressing of each projection to prevent the elastic member from slipping.
What is needed is a method of crankshaft damper assembly using interlocking beads whereby a predetermined shape is pressed into an elastomeric member. The present invention meets this need.